HRT alarm rings again

A study of more than a million women has identified a doubled breast cancer risk among users of a form of hormone replacement therapy, confirming research that caused widespread anxiety last year, and prompting Australian authorities to amplify health warnings.

The new British study tracked the health of post-menopausal women in Britain, half of whom were taking HRT, for an average 2 years.

The Million Women Study found a slightly elevated breast cancer risk among women who took oestrogen-only preparations - the equivalent of five extra cases for every 1000 women who took the treatment for 10 years. But among women who used combined oestrogen and progestogen for 10 years, there was an immediate increase in the breast cancer rate, rising to 19 extra cases among 1000 women - a more than doubled risk.

The results, derived from Britain's cancer registries, add weight to last year's United States Women's Health Initiative study. It too identified a doubled breast cancer risk, and found HRT users were more prone to heart attacks.

The relevance of the US study was challenged by some doctors because patients were typically in their mid-60s - older than most Australian HRT users. But in the British survey, published yesterday in The Lancet, the women's average age of 58 was closer to the Australian profile.

It supports previous advice that HRT should not be used for long-term disease prevention, says Martin Tattersall, chairman of an expert committee that revised official Australian advice last year.

But John Eden, director of the Sydney Menopause Centre at the Royal Hospital for Women, said: "Most Australian women who use HRT take it for one to two years for the relief of menopausal symptoms, and these women should not be concerned."

The chance of being killed in a car accident in NSW was more than double that of developing an HRT-related breast cancer, he said. Combined HRT protected against bowel cancer, he added.

Susan Davis, research director at Melbourne's Jean Hailes Foundation, said the British results could be biased as HRT was more popular among wealthier and better educated women, who drank more alcohol - itself a risk factor for breast cancer. Professor Davis said doctors were already prescribing cautiously. If hot flushes, sweating and mood disturbances were very debilitating, HRT should be considered. In not, HRT, routinely prescribed in the past, should generally be avoided.

She feared for women on oestrogen-only HRT after removal of ovaries, who would be at greater risk of osteoporosis if they quit.